Roof top coolers of the evaporative type are popular because of their low running costs and high output and efficiency in dry climates, and traditionally a roof top cooler is connected to large distribution conduits or ducts by means of a vertical trunk which is of size and shape to convey cooled air, and has a lower flange contiguous with the top of a roof, and an upper portion which supports the cooler.
Roofs, of course, vary considerably in structure and in slope, and therefore it is necessary for the trunk to be "tailored" to a specific roof requirement. As a consequence of that, it is usual for trunks to be formed from metal, and metal on a roof is liable to deterioration due to corrosion. If corrosion occurs, it is possible under extreme conditions for a cooler to lose its support on a roof and as a consequence of this in certain areas of the world, there are requirements to have legs which can engage the upper surface of a roof and which will support the cooler in a case of deterioration of the trunk.
However, the addition of legs can be quite costly both in manufacture and in installation, partly due to the variation of slope which is encountered in installation. Furthermore, legs need to be separately packed and some are likely to be of dimension which exceeds the width or length of a cooler, and this in turn requires separate packaging, which can cause delays in installation.
A cooler has a considerable weight, and it is believed that some of the proposals which have been made in prior art have been inadequate to support that weight under extreme conditions of weather and wind.